1. Field of Invention
The present invention relates to a terminal hardware used to connect to a terminal of a flat-type conductor.
2. Description of Related Art
A flexible flat cable (FFC) and a flexible printed circuit (FPC) are known as flat-type conductors. For example, a construction of an FFC is described as follows. Plural strips of conductors are aligned in parallel and covered and pressed by insulating sheets from both upper and lower sides. Thus, the FFC is formed to have a flexible ribbon-shape. There are two methods to connect terminal hardware to each of the conductors of the FFC as described above: a method that connects the terminal hardware to the conductor covered by the insulating sheet, and a method that connects the terminal hardware to the conductor exposed on one side by peeling the insulating sheet of the terminal.
The latter method is disclosed in Japanese Utility Model Laid-Open Publication No. Sho.63-73862, for example. As shown in FIG. 11, at the terminal of FFC 1, a predetermined amount of an insulating sheet 2 on the upper side is peeled, and a conductor 3 is exposed on the upper side. A terminal hardware 4 having a base plate 6 extending from a rear side of a connection portion 5 is provided to be connected to another terminal hardware. Further, a top plate 7 is integrally formed with the base plate 6 so as to face the base plate 6 and to be capable of being opened and closed with respect to the base plate 6. Claws 8 are provided at opposite side edges of the open end of the top plate 7.
A portion of the exposed conductor 3 is inserted between the base plate 6 and the top plate 7. The claws 8 pierce the FFC 1 on the lower side and are crimped to opposite side edges of the base plate 6. Thus, the FFC 1 is sandwiched between the base plate 6 and the top plate 7, and the top plate 7 is pressed against the conductor 3 to establish connection.
However, in the above-described method, since the entire surface of the flat-shaped top plate 7 contacts the conductor 3, the contact pressure becomes low. Thus, the reliability of electrical contact is poor.
Further, when a tension is applied in a longitudinal direction of the FFC 1, there is a possibility that the claws 8 separate from the FFC 1 (insulating sheet 2) and the terminal hardware becomes separated from the FFC 1, since the claws 8 are caught by the FFC 1 only at a portion where the claws positioned parallel to the tension pierce the FFC.
When a terminal hardware is connected to the conductor 3, which is exposed at a surface, there is a way to avoid the claws 8 piercing the FFC. In this case, the terminal of FFC is formed to have a comb-shape so that each portion where the conductor 3 is exposed is left as a tooth portion. The claws 8 hold the tooth portions of the comb-shape and are crimped thereto to fix the terminal hardware to the terminal of the FFC. However, the terminal hardware 4 is also easily separated from the terminal particularly in this case.
The present invention is provided to eliminate the above-described drawbacks. An objective of the present invention is to provide a terminal hardware for a flat-type conductor having a high contact pressure between a conductor and the terminal hardware, and a superior holding force against a tension.
To achieve the above and/or other goals, the present invention provides terminal hardware connected to a terminal end of a flat-type conductor having a conductor exposed on one surface. The terminal hardware includes a pair of plates that face each other and receive the conductor therebetween, and a crimping portion that projects from a side edge of one of the pair of the plates and that is bendable and crimpable to a side edge of the other one of the pair of the plates. An elongated projection is provided on one of the pair of the plates facing the exposed surface of the conductor, and is extended in a longitudinal direction of the pair of plates.
Further, an engaging and retaining portion, which is configured to engage with and retain the terminal end of the flat-type conductor, is provided on at least one of the pair of the plates and is located forwardly from the elongated projection in a direction in which the terminal hardware extends to engage with the flat-type conductor.
According to the features of the present invention, since the elongated projection forcefully presses against and indents the conductor, high contact pressure can be applied and consequently stable electrical connection can be achieved. Further, even when a tension tending to separate the terminal hardware from the flat-type conductor is applied, since an engaging and retaining portion that engages with and retains the conductor is provided, the holding power against the tension can be increased. In addition, the engaging and retaining portion is provided forwardly from the elongated projection in a direction to which the terminal hardware extends to engage with the conductor, the tension applied to the contact portion between the terminal hardware and the terminal end is effectively avoided.
The elongated projection can be located at approximately the same position in the longitudinal direction of the pair of plates as a position of the crimping portion. Thus, since the elongated projection forcefully presses against and indents the conductor more effectively, a higher contact pressure can be achieved. Preferably, the crimping portion is a pair of crimping portions projecting from opposite side edges of one of the pair of plates.
The engaging and retaining portion can be formed to have an undulating-shape. Accordingly, since the terminal hardware contacts the conductor at broader area, the reliability of the electrical contact can be increased.
Further, a piercing portion can be bent at a front end of one of the pair of plates facing the exposed surface of the conductor in a direction to which the terminal hardware extends to engage with the flat-type conductor. The piercing portion pierces the conductor. Accordingly, since the piercing portion pierces the conductor and provides a hook, the holding power against the tension tending to cause separation can be further increased.